A comparison of bronchodilating effects of salmeterol and oxitropium bromide in stable chronic obstructive pulmonary disease

N-formyl-l-aspartate: A novel sperm chemoattractant identified in ovulatory phase oviductal fluid using a microfluidic chip

BACKGROUND

Chemotaxis, as a mechanism for sperm guidance although known, has been difficult to demonstrate in vitro. Consequently, very few chemoattractants have been identified till date.

OBJECTIVES

To investigate sperm motility behavior in response to ovulatory (OV) and preovulatory (preOV) oviductal fluid (OF) and identify potential chemotactic metabolites.

MATERIALS AND METHODS

Intracellular calcium ([Ca²⁺ ]_I ) influx in capacitating sperm was determined by spectrofluorimetry. The chemotactic response of rat caudal sperm to OF from the preOV- and OV- phases of normally cycling female rats was assessed in a microfluidic device developed by us. Hydrophilic metabolites extracted from the OF of both the phases were resolved and identified by LC-MS/MS, followed by data analysis using XCMS and MetaboAnalyst software, and chemotactic potential of the most promising compound was validated using the microfluidic device.

RESULTS

Spectrofluorimetric analysis depicts a significant increase in sperm [Ca²⁺ ]_I in response to OV-OF. With the microfluidic chemotaxis assay, sperm population shows a significantly increased directionality and velocity to an ascending gradient of 0.06 µg/µl OV-OF compared to preOV-OF. LC-MS/MS of the OFs demonstrates five and four metabolites to be exclusive to the OV-OF and preOV-OF, respectively, and 25 metabolites common to both, of which 14 metabolites, including N-formyl-l-aspartate (NFA), are increased in OV-OF; NFA was tested for its ability to influence sperm movement, and shows chemotaxis potential.

DISCUSSION AND CONCLUSION(S)

This is the first study that has systematically demonstrated sperm chemotaxis with OV phase rat OF, identified NFA present in this fluid as a novel chemoattractant to sperm, and proven the utility of the device to test putative chemoattractants. It remains to be seen whether NFA is present in the follicular fluid (FF) of infertile women, and whether it may likely be a reason for the failure of natural conception in idiopathic infertile women.

Ability of using different dry powder inhalers during COPD exacerbations

BACKGROUND

Guidelines suggest that patients hospitalized for acute COPD exacerbations (AECOPD) are treated with short acting bronchodilators. Long acting bronchodilators, offer longer symptom relief but since they are usually administered via Dry Powder Inhalers (DPIs) it is considered that during AECOPD patients would not be able to achieve appropriate inspiratory flow (IF) to receive appropriate drug doses. The aim of the present study was to evaluate whether patients admitted to the hospital for AECOPD, are able to achieve the necessary IF using different DPIs.

METHODS

IF was measured daily in patients admitted for AECOPD with a portable IF meter (In-Check Oral inhaler assessment kit), containing a series of adapters that simulate the resistance of 4 DPIs [Turbuhaler (T), Breezhaler/Aerolizer (B/F), Discus (A/A/D) and Handinhaler (HH)]. Dyspnea, spirometry and arterial blood gases were also recorded daily.

RESULTS

44 consecutive patients were included in the study. The majority of patients were able to achieve an IF over 30 L/min with all four device resistances. This minimum required IF was achieved in 90.9%, 100%, 95.5% and 81.8% of patients on admission and in 100%, 100%, 97.7%, and 95.5% of patients on discharge for T, B/F, A/A/D and HH respectively. No functional characteristic was able to predict the achievement of this minimum necessary IF.

CONCLUSION

Most patients hospitalized for AECOPD, are able to receive treatment with long acting bronchodilators administered via DPIs. The possible beneficial effects of such an intervention should be tested in further studies.

Muscarinic Receptor Antagonists

Parasympathetic activity is increased in patients with chronic obstructive pulmonary disease (COPD) and asthma and appears to be the major reversible component of airway obstruction. Therefore, treatment with muscarinic receptor antagonists is an effective bronchodilator therapy in COPD and also in asthmatic patients. In recent years, the accumulating evidence that the cholinergic system controls not only contraction by airway smooth muscle but also the functions of inflammatory cells and airway epithelial cells has suggested that muscarinic receptor antagonists could exert other effects that may be of clinical relevance when we must treat a patient suffering from COPD or asthma. There are currently six muscarinic receptor antagonists licenced for use in the treatment of COPD, the short-acting muscarinic receptor antagonists (SAMAs) ipratropium bromide and oxitropium bromide and the long-acting muscarinic receptor antagonists (LAMAs) aclidinium bromide, tiotropium bromide, glycopyrronium bromide and umeclidinium bromide. Concerns have been raised about possible associations of muscarinic receptor antagonists with cardiovascular safety, but the most advanced compounds seem to have an improved safety profile. Further beneficial effects of SAMAs and LAMAs are seen when added to existing treatments, including LABAs, inhaled corticosteroids and phosphodiesterase 4 inhibitors. The importance of tiotropium bromide in the maintenance treatment of COPD, and likely in asthma, has spurred further research to identify new LAMAs. There are a number of molecules that are being identified, but only few have reached the clinical development.

Pharmacology and therapeutics of bronchodilators

Bronchodilators are central in the treatment of of airways disorders. They are the mainstay of the current management of chronic obstructive pulmonary disease (COPD) and are critical in the symptomatic management of asthma, although controversies around the use of these drugs remain. Bronchodilators work through their direct relaxation effect on airway smooth muscle cells. at present, three major classes of bronchodilators, β(2)-adrenoceptor (AR) agonists, muscarinic receptor antagonists, and xanthines are available and can be used individually or in combination. The use of the inhaled route is currently preferred to minimize systemic effects. Fast- and short-acting agents are best used for rescue of symptoms, whereas long-acting agents are best used for maintenance therapy. It has proven difficult to discover novel classes of bronchodilator drugs, although potential new targets are emerging. Consequently, the logical approach has been to improve the existing bronchodilators, although several novel broncholytic classes are under development. An important step in simplifying asthma and COPD management and improving adherence with prescribed therapy is to reduce the dose frequency to the minimum necessary to maintain disease control. Therefore, the incorporation of once-daily dose administration is an important strategy to improve adherence. Several once-daily β(2)-AR agonists or ultra-long-acting β(2)-AR-agonists (LABAs), such as indacaterol, olodaterol, and vilanterol, are already in the market or under development for the treatment of COPD and asthma, but current recommendations suggest the use of LABAs only in combination with an inhaled corticosteroid. In addition, some new potentially long-acting antimuscarinic agents, such as glycopyrronium bromide (NVA-237), aclidinium bromide, and umeclidinium bromide (GSK573719), are under development, as well as combinations of several classes of long-acting bronchodilator drugs, in an attempt to simplify treatment regimens as much as possible. This review will describe the pharmacology and therapeutics of old, new, and emerging classes of bronchodilator.

One hundred years of chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is an increasing health problem and one of the leading causes of morbidity and mortality worldwide, but knowledge about its pathogenesis has increased substantially in recent years. The disease results from interaction between individual risk factors (like enzymatic deficiencies) and environmental exposures to noxious agents, like cigarette smoking, occupational dusts, air pollution and infections in childhood. The main mechanisms that may contribute to airflow limitation in COPD are fixed narrowing of small airways, emphysema and luminal obstruction with mucus secretions. COPD is characterised by a chronic inflammatory process in the pulmonary tissue, with a pattern different from bronchial asthma, associated with extrapulmonary effects and is considered now a complex, systemic disease. Optimal therapeutic targeting of COPD depends on a clear understanding of the precise mechanisms of these complex processes and on early and correct evaluation of disease severity. A combination of pharmacological and non-pharmacological approaches is used to treat COPD. Bronchodilators are the mainstay of COPD treatment and can be combined with inhaled corticosteroids for greater efficacy and fewer side effects. The use of LTOT for hypoxemic patients has resulted in increased survival, and expanded drug therapy options have effectively improved dyspnoea and quality of life. Recent studies have documented the benefits of pulmonary rehabilitation. In addition, non-invasive mechanical ventilation offers new alternatives for patients with acute or chronic failure.

[Bronchodilators in COPD: latest recommendations, recent data and perspectives]

DEMONSTRATED EFFICACY: Inhaled bronchodilators improve the quality of life of COPD patients by reducing dyspnea and exacerbation frequency. There is no data supporting the superiority of one of the families of inhaled bronchodilators (i.e. beta 2 agonists and anticholinergic agents) over the other. Thus, the choice has to be based on the individual symptomatic response. These agents can be combined. OTHER POSSIBILITIES: Long-acting beta 2 agonists are already available and long-acting anticholinergics should be marketed soon. Theophylline has a lower efficacy/tolerance ratio than inhaled bronchodilators but can provide additional benefits when associated with the latter in some patients. Phosphodiesterase inhibitors with both bronchodilating and anti-inflammatory effect are being developed. THE BENEFITS OF CORTICOSTEROIDS: Finally, in symptomatic patients with FEV1<50% predicted and repeated exacerbations despite bronchodilators, inhaled corticosteroids can be added.

Muscarinic acetylcholine receptors and airway diseases

Parasympathetic nerves provide the dominant autonomic innervation of the airways. Release of acetylcholine from parasympathetic nerves activates postjunctional muscarinic receptors present on airway smooth muscle, submucosal glands, and blood vessels to cause bronchoconstriction, mucus secretion, and vasodilatation, respectively. Acetylcholine also feeds back onto prejunctional muscarinic receptors to enhance or inhibit further acetylcholine release. In asthma and chronic obstructive pulmonary disease, bronchoconstriction and mucus secretion is increased and the airways are hyperresponsive to contractile agents. These changes are due to increased parasympathetic nerve activity. The number and function of postjunctional muscarinic receptors in the airways are unchanged in animal models of asthma. Rather, it is the supply of acetylcholine to the postjunctional cells (smooth muscle and submucosal gland) that is increased. The increase in acetylcholine release occurs because prejunctional, inhibitory M(2) muscarinic receptors on the parasympathetic nerves are dysfunctional. M(2) muscarinic receptor dysfunction and subsequent airway hyperreactivity have been demonstrated to occur in animals in response to a variety of triggers, including antigen challenge, virus infection, ozone exposure, and vitamin A deficiency. In humans, there is evidence that loss of M(2) muscarinic receptor function is related to asthma. The mechanisms by which neuronal M(2) muscarinic receptor function is lost and its relevance to human airway disease are discussed in this review.

Management of Chronic Obstructive Pulmonary Disease: A Review

Chronic obstructive pulmonary disease (COPD) affects about 14 million persons in the United States and is the only common cause of death that is increasing in incidence. Chronic management of this disorder includes nonpharmacologic interventions such as smoking cessation, immunization, nutritional support, and pulmonary rehabilitation. The pharmacotherapy of COPD is based on regular administration of bronchodilators, when symptoms are persistent. Long-acting bronchodilators have been shown to improve quality of life in patients with COPD. Ipratropium remains the anticholinergic of choice, but more specific agents with a longer duration of action should become available. Four recent large clinical trials on the use of inhaled corticosteroids (ICS) have been published. The results demonstrate that ICS do not alter the decline in lung function in patients with COPD. Patients with more severe COPD and frequent exacerbations may have a better quality of life and a reduced rate of exacerbations with ICS. Management of acute exacerbations involves three major pharmacologic treatment modalities: antibiotics, short-acting bronchodilators, and systemic steroids. Recent data shows the benefits of systemic corticosteroids in the management of acute exacerbations.

Long-acting beta2 agonists in the management of stable chronic obstructive pulmonary disease

Long-acting beta2 agonist bronchodilators (e.g. formoterol, salmeterol) are a new interesting therapeutic option for patients with chronic obstructive pulmonary disease (COPD). In the short term, both salmeterol and formoterol appear to be more effective than short-acting beta2 agonists, and in patients with stable COPD they are more effective than anticholinergic agents and theophylline. Regular treatment of patients with COPD with long-acting beta2 agonists can induce an improvement in the respiratory function and certain aspects of quality of life. Moreover, salmeterol seems to be better than ipratropium and theophylline in improving lung function at the recommended doses after a long term treatment. Use of combination therapy of a long-acting inhaled beta2 agonist and an anticholinergic agent or theophylline in patients with COPD has not been sufficiently studied. Combination of usual doses of ipratropium or oxitropium with usual doses of salmeterol or formoterol does not appear to improve pulmonary function, but this lack of improvement with the combination should not, in itself, prevent implementation of further therapeutic steps in patients responsive to an anticholinergic agent and/or salmeterol or formoterol administered singly. Neither formoterol nor salmeterol elicit significant cardiovascular effects in healthy individuals and patients with reversible airway obstruction. However, adverse cardiac events might occur in patients with COPD with pre-existing cardiac arrhythmias and hypoxaemia if they use long-acting 12 agonists, although the recommended single dose of salmeterol 50 microg or formoterol 12 microg ensures a relatively higher safety margin than formoterol 24 microg. The bronchodilatory effect of long-acting beta2 agonists seems to be fairly stable after regular treatment with these bronchodilators. Moreover, pre-treatment with a conventional dose of formoterol or salmeterol does not preclude the possibility of inducing further bronchodilation with salbutamol in patients with partially reversible COPD. All these findings support the use of long-acting beta2 agonist bronchodilators as first-line bronchodilator therapy for the long term treatment of airflow obstruction in patients with COPD. However, since physicians must always choose a drug that is highly efficacious, well tolerated and inexpensive, the cost-effectiveness analysis in relation to other bronchodilators will determine the proper place of long-acting beta2 agonists in the long term therapy of stable COPD.

Bronchodilator therapy in chronic obstructive pulmonary disease

This paper reviews new developments in bronchodilator therapy for chronic obstructive pulmonary disease (COPD). Most patients with COPD respond to bronchodilators, but we have no reliable way to predict which patients will respond. When responsiveness is assessed, changes in lung volume as well as improvements in FEV1 should be considered. The combination of a beta-agonist and an anticholinergic agent produces greater improvement than either agent alone. Anticholinergic agents have few adverse side effects in patients with COPD, but concern remains about the possible cardiac side effects of beta-agonists. No clear answer exists about whether new, long-acting beta-agonists, such as salmeterol, should supplant anticholinergic agents as "first-line" therapy in COPD.

Acute effect of pretreatment with single conventional dose of salmeterol on dose-response curve to oxitropium bromide in chronic obstructive pulmonary disease

BACKGROUND

An earlier study documented that, in patients with chronic obstructive pulmonary disease (COPD), addition of ipratropium bromide at the clinically recommended dose (40 microg) does not produce any further bronchodilation than that achieved with salmeterol 50 microg alone. However, the dose of ipratropium bromide needed to produce near maximal bronchodilation is several times higher than the customary dosage. The full therapeutic potential of combined salmeterol plus an anticholinergic drug can therefore only be established using doses higher than those currently recommended in the marketing of these agents. A study was undertaken to examine the possible acute effects of higher than conventional doses of an anticholinergic agent on the single dose salmeterol induced bronchodilation in patients with stable and partially reversible COPD.

METHODS

Thirty two outpatients received 50 microg salmeterol or placebo. Two hours after inhalation a dose-response curve to inhaled oxitropium bromide (100 microg/puff) or placebo was constructed using one puff, one puff, two puffs, and two puffs-that is, a total cumulative dose of 600 microg oxitropium bromide. Dose increments were given at 20 minute intervals with measurements being made 15 minutes after each dose. On four separate days all patients received one of the following: (1) 50 microg salmeterol + 600 microg oxitropium bromide; (2) 50 microg salmeterol + placebo; (3) placebo + 600 microg oxitropium bromide; (4) placebo + placebo.

RESULTS

Salmeterol induced a good bronchodilation (mean increase 0.272 l; 95% CI 0.207 to 0.337) two hours after its inhalation. Oxitropium bromide elicited an evident dose-dependent increase in forced expiratory volume in one second (FEV(1)) and this occurred also after pretreatment with salmeterol with a further mean maximum increase of 0.152 l (95% CI of differences 0.124 to 0.180).

CONCLUSIONS

This study shows that acute pretreatment with 50 microg salmeterol does not block the possibility of inducing more bronchodilation with an anticholinergic agent when a higher than normal dosage of the muscarinic antagonist is used.

Influence of higher than conventional doses of oxitropium bromide on formoterol-induced bronchodilation in COPD

We examined the influence of higher than conventional doses of oxitropium bromide on formoterol-induced bronchodilation in patients with partially reversible stable COPD. Twenty outpatients inhaled one or two puffs of formoterol (12 microg puff(-1)), or placebo. Two hours after inhalation, a dose-response curve to inhaled oxitropium bromide (100 microg puff(-1)) or placebo was constructed using one puff, one puff, two puffs and two puffs, for a total cumulative dose of 600 microg oxitropium bromide. Doses were given at 20-min intervals and measurements made 15 min after each dose. On six separate days, all patients received one of the following: (1) formoterol 12 microg + oxitropium bromide 600 microg, (2) formoterol 12 microg + placebo, (3) formoterol 24 microg + oxitropium bromide 600 microg, (4) formoterol 24 microg + placebo, (5) placebo + oxitropium bromide 600 microg, or (6) placebo + placebo. Both formoterol 12 microg and 24 microg induced a good bronchodilation (formoterol 12 microg, 0.19-0.20 l; formoterol 24 microg 0.22-0.24 l). The dose-response curve of oxitropium, but not placebo, showed an evident increase in FEV1, with a further significant increase of respectively 0.087 l and 0.082 l after the formoterol 12 microg and formoterol 24 microg pre-treatment. This study shows that improved pulmonary function in patients with stable COPD may be achieved by adding oxitropium 400-600 microg to formoterol. There is not much difference in bronchodilation between combining oxitropium with formoterol 12 microg or 24 microg. In any case, formoterol 24 microg alone seems sufficient to achieve the same bronchodilation induced by oxitropium 600 microg alone in most patients.

Incremental benefit of adding oxitropium bromide to formoterol in patients with stable COPD

The effects of the long-acting beta(2)-agonist formoterol, the anticholinergic drug oxitropium bromide, and their combination were compared in 16 patients with partially reversible stable COPD. On each of 4 study days patients inhaled both drugs separated by 180 min in alternate sequence, with formoterol being administered in two doses (formoterol 12 microg + oxitropium bromide 200 microg; oxitropium bromide 200 microg + formoterol 12 microg; formoterol 24 microg + oxitropium bromide 200 microg; oxitropium bromide 200 microg + formoterol 24 microg). FEV(1)and FVC were measured baseline and after 30, 60, 120, 180, 210, 240, 300 and 360 min. In terms of onset of action, formoterol performed better than oxitropium bromide. Within the first 180 min after inhalation formoterol 24 microg was the most effective drug (maximal change in FEV(1): formoterol 24 microg = 25.6%, formoterol 12 microg = 21.1%, oxitropium bromide = 18.2%). Increased bronchodilation was obtained when the second drug was added, the sequence formoterol 24 microg + oxitropium bromide being the most effective (maximal change in FEV(1)over baseline: formoterol 24 microg + oxitropium bromide 28.8%, oxitropium bromide + formoterol 24 microg 20.9%, formoterol 12 microg + oxitropium bromide 26.6%, oxitropium bromide + formoterol 12 microg 22.5%). Significant improvement in pulmonary function may be achieved by giving two different bronchodilators in stable COPD patients. The sequence formoterol 24 microg + oxitropium bromide 200 microg seems to be the most effective.